The present invention relates to a printer equipped with a function for cutting paper.
Conventionally printers have been widely used in the home as output devices for fax machines and in establishments as output devices for Point of Sale (POS) units. Many of such printers print onto paper supplied from a roll. In recent years, however, compact printers such as ink jet printers have come into increasing use in homes and offices. These printers print onto standardized sizes, such as A4, of cut sheets or cut paper. In keeping with this trend, many recent fax or facsimile machines also use cut sheets, with such machines becoming increasingly common in the home.
However, compared to printers that use cut sheets, roll paper-type printers have an advantage in that it is easier to make the overall size of the printer compact. In the case of a cut-sheet printer, a printer that can print on cut sheets of a given size such as A4 (21 cm by 29 cm), the printer needs to be at least big enough to store A4 sheets (21 cm by 29 cm) in a laid-out manner. On the other hand, a roll paper-type printer needs to be as wide as the A4 size (21 cm for example), but only sufficiently deep to accommodate the diameter of the roll, which can be only a few centimeters across, for example.
In recent years, in particular there has been demand for printers that can be carried with a mobile computer (mobile terminal), such as a mobile phone or a PDA (Personal Data Assistant), and can be connected to such a mobile computer so that printing becomes easily performed in any location. Small, slimline printers that can print on A6 size (10.5 cm by 4.8 cm), for example, or smaller paper are desired. Since the overall sizes of roll-paper type printers are more compact than those of cut sheet-type printers, roll-paper type printers are well-suited to use as portable, compact, slimline printers.
Compared to a serial-type printer, in which printing is performed while a print head is traveled in the scanning direction, it is easier to produce a thermal-type printer, which has a line thermal head and a platen roller for feeding paper while pressing the paper onto the line thermal head, as a compact printer since there is no need for space in which to run the print head in the scanning direction or for a mechanism for moving the print head. If thermal paper is used, there is no need for consumables such as ink, toner or an ink ribbon, which makes maintenance easier and makes it unnecessary to provide space for storing the consumables. This means that thermal paper is especially suited to compact, portable printers. For these reasons, paper-roll-type line printers can be produced in slimline, compact designs, making them suitable as printers that are carried along with PDAs or mobile phones and are used together with such devices, or as printers for personal use that can be used in place of a conventional memo pad.
Printers also need to be user-friendly devices. When a paper-roll type printer is used, the printed paper that is discharged from the printer needs to be cut into sheets of a desired size, so that some paper-roll type printers can be cumbersome to use. While it is possible to provide a blade at the discharge slot to enable the user to manually cut the printed paper that is discharged, when a plurality of pages are printed out consecutively, the print operation has to stop every time a page has been printed out so that the page can be manually cut off the roll, making the printing operation cumbersome. On the other hand, a plurality of pages may be consecutively printed, though in such case the user then has to go to the trouble of cutting the paper roll into separate pages.
Some conventional A4 fax machines are equipped with a cutter for automatically cutting the printed paper roll into A4-sized sheets. There is no need for the user to cut each page by hand, and a page by page printout, not a continuous printed roll, is obtained when a multiple page document is received. However, there are a number of problems when incorporating this kind of cutter mechanism into an A6 or smaller portable, slimline printer as mentioned above. A first problem is how to incorporate a cutter in a compact manner without increasing the bulkiness of the printer. Unlike a fax machine or a conventional desktop printer where there are no particular problems if the thickness and width or length are several dozen centimeters, a postcard or business card size printer has to be compact and slimline (for example, a thickness of between a few centimeters and 1 cm, or less) with a width and length of a few centimeters, and it is preferable for the cutter mechanism to be added without changing the size of the printer.
It is also extremely difficult to completely prevent paper jams from occurring for a printer, so that a printer needs to have a construction that makes it possible to remove a paper jam. When a cutter mechanism is provided, the cutter makes it difficult to access the paper feeding path and to remove the paper jamming the printer from the paper path. In particular, in the type of compact, portable printer described above, the paper path (paper feeding route) is designed to be virtually the most compact route possible, so that it is very difficult to come up with a design that makes it easy for users to remove paper jams. When a cutter mechanism is additionally provided, it becomes even more difficult to remove a paper jam. In order to stop excessively large margins being left on the printed roll, the cutter should preferably be disposed so as to cut the paper as close as possible to the line thermal head. Also, to make the overall design of a printer compact, it is preferable to position the cutter mechanism as close as possible to the thermal head and the platen roller. This means that the cutter prevents access to the point at which the paper is held between the thermal head and the platen roller, so that it is difficult to provide a compact, portable printer that is easy to use anytime and anywhere.
It is a first object of the present invention to provide a compact printer which uses a paper roll and is internally provided with a cutter mechanism, and with which paper jams can be easily removed. It is a second object of the present invention to provide a compact printer that can be carried together with a mobile terminal, is easy to maintain, and can print reliably wherever the printer is used.
A printer according to the present invention uses a cutter mechanism that includes a movable blade and a fixed blade. The printer also includes a line thermal head and a platen roller and one of the line thermal head and the platen roller can be moved to a position (the second position) where paper jams can be removed, and one of the fixed blade and the movable blade directly or indirectly attached to one of the line thermal head and the platen roller so that when the line thermal head or platen roller is moved to the second position, one of the movable blade and the fixed blade is also moved together with one of the line thermal head and the platen roller. This is to say, the printer of the present invention includes: a line thermal head; a platen roller for holding a paper between the platen roller and the line thermal head and feeding the paper; a cutter, including a movable blade and a fixed blade, for cutting printed paper; and a cutter driving mechanism for driving the movable blade, wherein at least one of the line thermal head and the platen roller can be moved from a first position for printing to a second position for removing a paper jam, and one of the movable blade and the fixed blade is directly or indirectly attached to one of the line thermal head and the platen roller so that when the one of the line thermal head and the platen roller moves from the first position to the second position, one of the movable blade and the fixed blade also moves together with the one of the line thermal head and the platen roller.
First, with the printer according to the present invention, at least one of the line thermal head and platen roller that hold the paper can be moved or removed, so that when a paper jam has occurred, at least one of these components can be moved to the second position that is above or below, in front or behind, or left or right relative to the first position, thereby releasing the paper from between the line thermal head and the platen roller and making it easy for the paper jam to be removed or solved. In the present invention, the second position does not refer to only a fixed position, and also includes positions away from the printer main body to which the line thermal head or the platen roller is moved to relative to the first position in an up-down, front-back, or left-right direction. The cutter is realized by a combination of a movable blade and a fixed blade, with either of these blades being attached to the line thermal head and the other being attached to the platen roller, so that when the line thermal head or the platen roller is moved, the movable blade or the fixed blade is also moved. This means that there is no need to remove the cutter before moving the line thermal head or the platen roller and that the movable blade or the fixed blade is moved by moving the line thermal head or the platen roller, so that the cutter does not block access to a path where paper jams occur.
By moving the line thermal head or the platen roller, the paper that is held between the line thermal head and the platen roller is released and paper that is held due to the engagement of the movable blade and the fixed blade or by improper engagement of the movable blade and fixed blade is also released due to the movement of the movable blade or the fixed blade. Accordingly, with the printer according to the present invention, paper even if the paper is held by the cutter, when a paper jam has occurred, can be released merely by an operation that moves or removes the line thermal head or the platen roller. Either the movable blade or the fixed blade moves, so that the cutter does not obstruct the movement of the line thermal head or the platen roller and the cutter does not obstruct the removal of the paper. This means that even though the printer is equipped with a cutter, maintenance is extremely easy, and paper jams can be easily removed.
By attaching the movable blade and the fixed blade to the line thermal head and platen roller respectively, the cutter can be disposed as close as possible to the line thermal head. Also, by attaching the movable blade and the fixed blade to the line thermal head and platen roller respectively, the movable blade and the line thermal head, for example, can be provided as a single unit and the fixed blade and the platen roller can be provided as another single unit. The printer can be made compact, and the printer becomes easier to assemble, making the printer suited to use as a slimline, compact printer. By combining the above components into single units, it becomes no longer necessary to provide components and it""s space for supporting the movable blade or fixed blade from the housing or chassis of the printer, which reduces the burden of producing the housing or chassis and is very effective at reducing the required amount of space. As one example, by assembling the unit in which the movable blade is attached to the line thermal head and the unit in which the fixed blade is attached to the platen roller to the housing or chassis, the number of assembly processes is reduced. There is also a reduction in the number of attachment processes for tight spaces and alignment adjustments, which simplifies the assembly of the printer.
In this way, the printer of the present invention makes it easy to remove paper jams and has a construction which from the viewpoint of the ease of assembly is suited to compact printers. Since there are reductions in the number of parts and in the number of assembly processes, a compact printer can be provided at low cost. According to the present invention, a printer that is easy to use anywhere and at any time can be provided at low cost. This printer includes printers that can store roll paper and printers where a roll paper cassette can be attached and detached.
In view of easy disassembling for removing paper jams, when the line thermal head and the platen roller are at the first position where printing can be performed, it is preferable for the movable blade to be disposed at a direction of the second position with respect to the fixed blade, which is to say, in the direction the line thermal head or the platen roller will move, so as to the movable blade moves together with the one of the line thermal head and the platen roller. When a paper jam has occurred, it is believed that there will be cases where the movable blade cannot be backed to the home position. In such cases, withdrawing the movable blade makes the paper feeding route normal and the paper jam can be removed easily. In order to withdraw a movable blade that has not returned to the home position, it is preferable for the movable blade to be on a side to which the movable blade is withdrawn to the fixed blade.
In a compact printer, there are cases where the platen roller has a small diameter and it is easy for find space for moving the movable blade close to the line thermal head. In such cases, it is preferable for the movable blade to be attached to the line thermal head and for the fixed blade to be attached to the platen roller. When the fixed blade is attached to the platen roller, the shaft of the platen roller can be used as the fitting points for installing the fixed blade. When the movable blade is attached to the line thermal head, a support plate to which the line thermal head is attached can be used as the fitting parts, with the movable blade being disposed so as to slide along the support plate.
On the other hand, it is also effective to construct a printer so that the movable blade moves together with the platen roller. If the platen roller can be removed, it becomes possible to access the entire paper feeding route when setting the roll paper or removing a paper jam. This makes it extremely easy to set the roll paper and remove a paper jam.
Printers often have a housing or chassis with a flat surface on the side from which printed paper is discharged, and it is preferable for the movable blade to be disposed so as to work along this flat surface. By disposing the movable blade in this way, the space that is required in the thickness direction of the movable blade to work can be minimized. This means that sufficient space for the movable blade to slide can be provided with almost no increase in the thickness of the printer. By arranging gears and/or arms included in the cutter driving mechanism parallel to the movable blade along the flat surface where the paper is discharged, the cutter driving mechanism can also be provided in a slimline space, so that a compact, slimline printer can be provided.
In a printer with a main driving mechanism where gears for driving the platen roller are disposed along a first surface that is perpendicular to the shaft of the platen roller, it is preferable for the gears and/or arms included in the cutter driving mechanism to be disposed along a second surface that is perpendicular to the first surface and to include an engaging unit or linking part for linking to one of the gears of the main driving mechanism for obtaining power. By providing the cutter driving mechanism not like the main driving mechanism on the first surface that is perpendicular to the shaft of the platen roller but on a second surface that is the upper or lower surface of the printer and where space is available, the cutter driving mechanism can be disposed without increasing the size of the printer in the width direction. By arranging the gears and/or arms that form the gear train in a space on the upper or lower surface of the printer, the cutter driving mechanism can be provided with very little increase in the size of the printer in the thickness direction. By disposing the movable blade so as to slide along the second surface parallel to the cutter driving mechanism, sufficient space for allowing the movable blade to work can be provided with very little increase in the size of the printer in the thickness direction. Accordingly, it is possible to provide a compact, slimline printer that is equipped with a cutter mechanism.
In these printers, the movable blade slides across and along a flat surface includes a reciprocating cutter that performs linear motion and a scissors-type cutter where the movable blade revolves. A scissors-type cutter has a simple driving mechanism, though it is necessary to provide the pivot for the rotation slightly away from the paper feeding route. A reciprocating cutter has a slightly complicated driving mechanism, though the space required for the movement of the movable blade is the most compact, which makes it easy to produce a printer that is compact overall.
The cutter driving mechanism can be driven by the motor that drives the main driving mechanism for rotating the platen roller. In this case, by driving the platen roller when the motor rotates forwards and the movable blade of the cutter when the motor rotates backwards, the platen roller and the cutter can be separately driven merely by controlling the direction of rotation of the motor that drives the platen roller.
In order to make the platen roller or line thermal head detachable, the movable blade that is attached to the platen roller or line thermal head and the cutter driving mechanism is also detachable, so that it is preferable that the engaging unit of the cutter driving mechanism is detachable from the main driving mechanism. When the movable blade is moved together with the platen roller, it is preferable for one of the gears in the main driving mechanism that drives the platen roller to be able to disengage.
Also, with the printer of the present invention, by providing the cutter driving mechanism with a single revolution mechanism whereby the movable blade is driven so as make one reciprocal movement between a home position that is away from the fixed blade and a cutting position when the movable blade operates in cooperation with the fixed blade to cut the paper, the movable blade makes on return movement where the paper is cut and the movable blade returns to the home position, which simplifies the position control over the movable blade. This prevents problems such as the occurrence of paper jams due to the gap between the movable blade and the fixed blade becoming too small during printing.
Blades where the edges are cut from plates can be used as the movable blade and the fixed blade. A movable blade and a fixed blade with this kind of edge can be easily manufactured by press working, which can lower the cost of the cutter. By using this kind of movable blade and fixed blade and disposing the blade edges of both so as to cross one another in an almost parallel state where the edges are tilted by only a very small clearance angle, a sharp cutting action can be maintained over a long period. In order to achieve a sufficient shearing force at the edge parts where the movable blade and the fixed blade touch one another, a clearance angle needs to be provided, though the cutter will become blunt if precautions are not taken to ensure that there will be no significant change in this angle even if abrasion occurs. For this reason, the fixed blade and the movable blade are arranged so as to engage one another in a parallel state while maintained a very small clearance angle, so that even if abrasion occurs, there is no change in the angle at which the tips of the movable blade and the fixed blade come into contact. The durability of the cutter may also be improved by subjecting the fixed blade and the movable blade to a hardening process, such as by sputtering a super-hard material onto the edges of the movable blade and the fixed blade.
It is also preferable for at least one of the movable blade and the fixed blade to be made of a thin metal plate that is flexible. By making at least one of the movable blade and the fixed blade out of a flexible metal plate, the movable blade and fixed blade can be made with the flexible blade being elastically deformed, so that the edges of the movable blade and the fixed blade can be reliably brought into contact and the paper can be reliably cut. Also, in order for the blade edges of the movable blade and the fixed blade that are elastic or flexible to reliably engage and operate, it is preferable for a guide part for guiding, at a position out of the paper, so that a blade edge of the movable blade engages a blade edge of the fixed blade.